Radiation curable compositions, such as coating and adhesive compositions, are used in a wide variety of applications. These compositions are cured by a photocuring process that involves the radiation induced polymerization or cross linking of polymerizable materials into a three dimensional network. Often it is desirable to use radiation curable compositions because they can require little or no volatile solvents, which is, of course, beneficial because of the demands to eliminate volatile organic compounds from coatings and adhesives. Energy savings, high throughput rates (low cure times), and low energy requirements are also often strong driving forces behind the use of radiation curable compositions. Radiation curable compositions can be applied to virtually any type of substrate, such as plastic, glass, textile, fabrics, leather, metal, paper, and wood, among others.
Radiation curable compositions are often based on unsaturated polyesters, styrene and/or acrylate compounds, wherein polymerization is initiated by a free radical mechanism that is oxygen inhibited unless effected in an inert atmosphere, such as under a blanket of nitrogen. Although formulation with certain photoinitiators, such as those that undergo a bimolecular reaction with a hydrogen donor can reduce the inhibitory effect of air, this benefit is often realized at the expense of a reduced cure rate. Moreover, styrene and certain acrylates are known as sensitizers and skin irritants as well as being carcinogenic, so that specialized safety precautions must be taken to protect personnel from exposure.
Vinyl ether containing compounds (monomers, oligomers and polymers) are sometimes utilized in radiation curable compositions. These compounds can cure by both cationic and free radical mechanisms and generally do not exhibit the extent of the toxicity issues previously described with respect to styrene and acrylates.
In many cases, it is desirable to spray apply radiation curable compositions. One drawback, however, to the use of certain relatively inexpensive multifunctional vinyl ethers, such as triethylene glycol divinyl ether, in a spray application is that these materials are of relatively low molecular weight and, accordingly, often too volatile for practical use in a spray application. Multifunctional vinyl ethers of reduced volatility, on the other hand, are often significantly more expensive than their low molecular weight counterparts.
As a result, novel vinyl ethers that can be relatively inexpensive to produce and which can exhibit reduced volatility, such that they are suitable for use in, for example, radiation curable compositions, such as coating and adhesive compositions, are desired.